Climate change threatsClimate action window could close as early as 2023

As the Trump administration repeals the U.S. Clean Power Plan, a new study from the University of Michigan underscores the urgency of reducing greenhouse gas emissions—from both environmental and economic perspectives.

For the U.S. most energy-hungry sectors—automotive and electricity—the study identifies timetables for action, after which the researchers say it will be too late to stave off a climate tipping point.

And the longer the nation waits, the more expensive it will be to move to cleaner technologies in those sectors—a finding that runs contrary to conventional economic thought because prices of solar, wind and battery technologies are rapidly falling, they say.

U-M notes that steps outlined in the Clean Power Plan, as well as in the 2016 Paris climate accord, would not have been enough to meet the goal of keeping global temperature increase to 2 degrees Celsius by the end of this century, the study shows.

To achieve the 70 percent reduction target for carbon dioxide emissions used in the study, additional steps would be needed—and before 2023. The window for effective action could close that early.

“If we do not act to reduce greenhouse gas emissions forcefully prior to the 2020 election, costs ​to reduce emissions at a magnitude and timing consistent with averting dangerous human interference with the climate will skyrocket,” said Steven Skerlos, U-M professor of mechanical engineering. “That will only make the inevitable shift to renewable energy less effective in maintaining a stable climate system throughout the lives of children already born.”

Before Trump’s reversal of both the domestic and international climate plans, the Intergovernmental Panel on Climate Change had recommended a 70 percent cut in carbon dioxide emissions from industrialized nations such as the U.S., where nearly half of emissions come from the electric and automotive sectors.

Using a custom, state-of-the-art model of these sectors, the researchers showed that the window for initiating additional climate action would close between 2023 and 2025 for the automotive sector and between 2023 and 2026 for the electric sector.

“That’s true under even the most optimistic assumptions for clean technology advancements in vehicles and power plants,” said study lead author Sarang Supekar, a mechanical engineering postdoctoral fellow at U-M.

Withdrawal from the accord and the EPA’s plan to repeal the Clean Power Plan will only make the chances of achieving the goal more remote, the researchers say.